It is of increasing interest to develop high-performance antioxidants for polypropylene (PP). Here, we have developed an organic-inorganic hybrid antioxidant by direct intercalation of low-molecular-weight hindered phenolic antioxidant (AO) into the interlayer region of layered double hydroxides (LDH), prepared the AO-LDH/PP composites following a simple solvent washing method, and investigated the thermal stability of the AO-LDH/PP composites by an accelerated aging method at 150 degrees C under air atmosphere. The results show that the one-step synthesis method is available to produce the AO-LDH with a basal spacing of 2.8 nm and that the addition of AO-LDH does not influence the crystallization behavior of PP. Furthermore, the radical-scavenging ability of AO-LDH is similar to that of the AO species. The AO-LDH significantly improves the long-term thermal stability of PP related to the CO3-LDH. The AO-LDH exhibits excellent antioxidative performance with promising applications in the field of polymers.